Suggestions:
A measurement unit is a standard quantity used to express a physical quantity. System has a validation in all receipt option to allow decimal places as per the unit of measure. In the unit of measure master, field name ‘decimal ‘ to define decimal places for any particular unit. i.e The number of decimals in which this unit holds.
The System should allow decimal places in quantity only as per the definition in UOM. If the definition is not UOM (unit of measurement) then it should allow 3 decimal.